﻿Module Funciones
    Public Function istex(ByVal texto As TextBox) As Boolean
        Dim band As Boolean
        Dim i As Integer
        band = True
        i = 0
        While (band = True And i < texto.Text.Length)
            If (Char.IsNumber(texto.Text, i)) Then
                band = False

            End If

            If (band = False) Then
                MessageBox.Show("DEBE INGRESAR UN VALOR DE TIPO TEXTO", "ERROR", MessageBoxButtons.OK, MessageBoxIcon.Error)
                texto.Text = ""
                texto.Focus()
                Exit Function
            End If
            i = i + 1
        End While
        Return band
    End Function

End Module
